Field of the Invention
The present invention relates to a photoresist film, and more particularly, a photoresist film and a manufacturing method for an organic light emitting display device using the same.
Discussion of the Related Art
An organic light emitting display (OLED) device is one of new flat display devices, and the OLED device can emit light in itself. In comparison with a liquid crystal display (LCD) device, the OLED device has a wider viewing angle and a greater contrast ratio. Furthermore, the OLED device does not require an additional backlight unit, whereby the OLED device can realize thin profile and light weight. Also, the OLED device is advantageous in power consumption. In addition, the OLED device has rapid response speed, and the OLED device can be driven by a low direct-current (DC) voltage, and also be manufactured at a low manufacturing cost.
In order to pattern an emitting layer (EML) between two electrodes on a substrate of the OLED device, a fine metal mask (FMM) method or an inkjet method has been used.
However, it is difficult to apply the FMM method to a large-sized and high-resolution device due to limitations of mask-manufacturing technology. Also, the FMM method may have a problem of sagging mask due to a weight of mask. Since the inkjet method uses a liquid-type material, it might lower functional efficiency of a light-emitting device exposed for a manufacturing process. Especially, in case of methods using a related art etching process, the light-emitting device is brought into direct contact with a solution for etching metal, whereby a disconnection might occur, or device characteristics might be deteriorated.
In order to overcome these problems, a lift-off process has been introduced, which enables a minute pattern even though only exposing and development steps are performed without an etching step during a photo-masking process including exposing, development and etching steps.
However, a dry film resist (DFR) corresponding to a related art photoresist film has a strong adhesive strength. Thus, in a step of removing a photoresist pattern, a residual layer may occur. That is, the residual layer may induce defects in the emitting layer (EML), to thereby lower efficiency of device.
A thermo-responsive polymer is a material showing a reversible phase transition by a rapid solubility difference of polymer according to a temperature change in an aqueous solution.
The thermo-responsive polymer may be largely classified into a material with a lower critical solution temperature (LCST) and a material with an upper critical solution temperature (UCST). The thermo-responsive polymer with the LCST, for example, has hydrophobic properties at a temperature of the LCST or higher than the LCST, whereby a phase separation occurs.
Generally, the thermo-responsive polymer has been used for controlling a drug release in a medical field. In recent years, the thermo-responsive polymer has attracted attentions owing to studies for application in various fields.